Azlactone-derivatized polyamides

ABSTRACT

The present invention relates to an azlactone-derivatized polyamide shaped article made by reacting at least one polyamide with a solution comprising an aza-bicyclo compound and a vinylazlactone derivative of the formula I                    
     wherein R 1 , R 2 , R 3 , R 4 , and R 5  are defined herein.

The invention relates to azlactone-derivatized polyamides, to shapedarticles comprising azlactone-derivatized polyamides, and to processesfor their preparation.

Azlactone-derivatized carrier materials are known from the literature;for example, U.S. Pat. No. 4,737,560 discloses crosslinked carriermaterials which comprise azlactone groups. EP 0 392 783 disclosesprocesses for the graft polymerization of substrate polymers, where thegrafted-on side chains comprise aclactone [sic] groups. These carriermaterials are suitable for binding proteins insofar as the azlactonegroups are sufficiently accessible to compounds of high molecular mass.Porous membranes of polyamides exhibit outstanding flow properties;membranes of polyamides can also be produced with pores whose internalsurfaces are readily accessible to compounds of high molecular mass.Polyamides, moreover, exhibit low levels of nonspecific binding withrespect to proteins.

The patent application DE 195 01 726.9 (WO 96/22 316) disclosesderivatized polyamide membranes which are in the form of block polymers.The monomers polymerized on can also be reacted to form azlactonegroups. The preparation of these azlactone-containing polyamidemembranes is relatively complex, since first of all it is necessary toprepare a polymerizable derivative of the polyamide and then the blockpolymer has to be prepared, with the monomers used in its preparationincluding precursor compounds for the azlactone group. Finally, theprecursor compounds must be converted into the azlactone group. Theobject is therefore to provide a simplified process for preparingazlactone-derivatized polyamides.

It has been found that amino groups, which are usually presentterminally in polyamides, can be reacted with vinylazlactonederivatives, the vinyl group reacting with the amino group to produce,in a simple manner, an azlactone-derivatized polyamide. Since theazlactone group is known to react with amino groups, this reactionpossibility is unexpected. Where the polyamides used as the substratepolymer contain carboxyl groups, these carboxyl groups can first of allbe reacted with diamino compounds by the process disclosed in DE 196 24813.2 (PCT/EP97/02 768) to provide additional amino groups.

The invention provides azlactone-derivatized polyamides obtainable byreacting polyamides with a solution comprising an azabicyclo compoundand a vinylazlactone derivative of the formula I

in which

R¹, R² and R³ independently of one another denote H or CH₃;

R⁴ and R⁵ independently of one another denote H or C₁- to C₅-alkyl.

Preferably, R¹, R² and R³ are H and R⁴ and R⁵ are methyl.

The invention provides for the use of the azlactone-derivatizedpolyamides for the binding of amino-containing compounds. Examples ofsuitable amino-containing compounds are proteins, including enzymes andantibodies.

The invention provides separation materials obtained by reacting anazlactone-derivatized polyamide of the invention with anamino-containing separation effector. Examples of suitableamino-containing separation effectors are antibodies and other affinityligands for affinity chromatography. Other separation effectors areknown to the person skilled in the art.

The invention provides immobilized enzymes obtainable by reacting anazlactone-derivatized polyamide of the invention with an enzyme.

Polyamides suitable as the base polymer are known to the person skilledin the art and are also obtainable commercially. They include, forexample, the polymers known under the trade name NYLON®, e.g. NYLON® 66and NYLON® 6. Porous or nonporous shaped articles consisting of suchpolyamides are likewise known and are also obtainable commercially; theyinclude, for example, bead-shaped articles, membranes, hoses, hollowfiber membranes, and sponges. The reaction of such shaped articles ispreferred, since under the reaction conditions as used in DE 195 01726.9 and DE 196 24 813.2 (reaction temperature below 80° C.) theirshape is retained whereas other processes for derivatizing polyamide areperformed in the melt or in solution.

The reaction sequence of the invention is preferably performed atbetween 0 and 70° C., in particular at between 10 and 60° C.; that is,at temperatures below the melting point of the starting polyamide. Sincethe starting polyamide need not be dissolved, the reaction sequence ofthe invention can preferentially also be applied to polyamide mouldingswithout any notable change in their form. The reaction is catalyzed byazabicyclo compounds, examples being 1,8-diazabicyclo-[5.4.0]undec-7-ene(DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). The vinylazlactone derivativeis dissolved together with the catalyst in a solvent which is inert tothe azlactone derivative. Preferred solvents are those which do notattack the polyamide; examples are dimethylformamide (DMF) and dimethylsulfoxide (DMSO).

Even without further statements it is assumed that a person skilled inthe art will be able to utilize the above description in the widestscope. The preferred embodiments are therefore to be interpreted merelyas a descriptive disclosure which in no way has any limiting naturewhatsoever.

The complete disclosure content of all above- and belowmentionedapplications, patents and publications, and of the correspondingapplication(s) DE 196 27 302.1, filed on Jun. 7, 1996, are herebyincorporated by reference into this application.

EXAMPLES

The examples which follow are intended to illustrate the invention anddo not constitute any restriction of the invention.

In the text below, room temperature means a temperature of between 15and 30° C.

Example 1 Reacting a Polyamide Hollow Fiber Membrane WithVinyldimethylazlactone

2.56 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 32 ml ofvinyldimethylazlactone are dissolved in 160 ml of dimethylformamide. Apolyamide hollow fiber bundle (polyamide 6, 64 filaments; individualfiber diameter; internal 0.2 mm, external 0.5 mm; average pore width 0.5μm) is packed into a 300-10 mm SUPERFORMANCE® chromatography column(from E. Merck) and the above solution is pumped in circulation at roomtemperature and with a flow rate of 2 ml/min through the hollow fiberbundle for 24 hours. Subsequently, the derivatized hollow fiber bundleis rinsed with dimethylformamide, acetone, ethyl acetate and acetone andis dried in a vacuum drying cabinet at 50° C.

Example 2 Binding γ-Globulin to a Vinyldimethyl-Azlactone-ActivatedPolyamide Hollow Fiber Membrane

1 g of γ-globulin is dissolved in 100 ml of Tris buffer (50 mM, pH 7.4)and this solution is pumped in circulation at room temperature throughthe hollow fiber bundle derivatized in accordance with Example 1 (flowrate: 5 ml/min). During this procedure, the protein concentration in thesolution and its decrease were determined continuously by means of UVspectrophotometry; after two hours, the protein concentration in thepump-circulated solution remained constant. After washing out the hollowfiber bundle with Tris buffer (50 mM, pH 7.4) and 0.1 M acetic acid, theamount of protein covalently bound in the hollow fiber bundle wasdetermined as 66.5 mg.

A hollow fiber module with a polyamide membrane coated with γ-globulinas described above can be used for affinity chromatography, for thebinding of anti-γ-globulin antibodies.

Example 3 Reacting A Polyamide With Ethylenediamine

To carry out the synthesis a polyamide hollow fiber bundle made frompolyamide 6 is packed in a 300-10 mm SUPERFORMANCE® chromatographycolumn (from E. Merck). An inert pump is attached to this column. Forthe reaction, 10 mol of ethylene diamine and 0.2 mol of1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) are dissolved in 200ml of 0.1 M sodium acetate buffer (pH 4.7) and pumped in circulation ata fast rate (5 ml/min) at room temperature for 5 hours. Subsequently,the derivatized membrane is washed to neutrality with 1 M phosphatebuffer pH 7 and with water.

Example 4 Reacting A Polyamide Hollow Fiber Membrane WithVinyldimethylazlactone

The reaction of the polyamide amino-modified in accordance with Example3 is performed as described in Example 1.

What is claimed is:
 1. An azlactone-derivatized polyamide shaped articlemade by reacting at least one polyamide shaped article with a solutioncomprising a catalytically effective amount of an aza-bicyclo compoundand a vinylazlactone of the formula I

in which R¹, R² and R³ independently of one another denote H or CH₃; R⁴and R⁵ independently of one another denote H or C₁- to C₅-alkyl.
 2. Anazlactone-derivatized polyamide shaped article according to claim 1,wherein carboxyl groups of the polyamide are reacted with a diaminocompound prior to the reaction with the vinylazlactone of the formula I.3. An azlactone-derivatized polyamide shaped article according to claim2, which is porous.
 4. An azlactone-derivatized polyamide shaped articleaccording to claim 1, which is porous.
 5. An azlactone-derivatizedpolyamide shaped article according to claim 1 wherein only one azlactoneradical from the compound of formula I is attached to each polyamidereaction site.
 6. An azlactone-derivatized polyamide shaped articleaccording to claim 1, which is a bead, a membrane, a hose, a hollowfiber, or a sponge.
 7. An azlactone-derivatized polyamide shaped articleaccording to claim 1 wherein R¹, R², and R³ are H and R⁴ and R⁵ aremethyl.
 8. An azlactone-derivatized polyamide shaped article accordingto claim 1, wherein the azlactone-derivatized polyamide shaped articleis only surface-modified by the catalytically effective amount of anaza-bicyclo compound and a vinylazlactone.
 9. A method of binding anamino-containing compound comprising contacting at least oneamino-containing compound with the azlactone-derivatized polyamideshaped article of claim
 1. 10. A process for making anazlactone-derivatized polyamide shaped article comprising: reactingunder basic conditions a polyamide shaped article with a solutioncomprising a catalytically effective amount of an azabicyclo compoundand a vinylazlactone of formula I

in which R¹, R² and R³ independently of one another denote H or CH₃; R⁴and R⁵ independently of one another denote H or C₁- to C₅-alkyl; whereinonly one azlactone radical from the compound of formula I is attached toeach polyamide reaction site.
 11. An azlactone-derivatized polyamideshaped article made by surface-modifying at least one polyamide shapedarticle with a solution comprising a catalytically effective amount ofan aza-bicyclo compound and a vinylazlactone of the formula I

wherein R¹, R² and R³ independently of one another denote H or CH₃; R⁴and R⁵ independently of one another denote H or C₁- to C₅-alkyl; andonly one azlactone radical from the compound of formula I is attached toeach polyamide reaction site.